The invention relates to a spinning machine having several spinning stations for the spinning of yarns from slivers which are fed to the spinning stations in cans, guiding devices for the slivers being provided between the cans and the spinning stations.
The feeding of the fiber material to be spun in the form of slivers disposed in cans is known, for example, in the case of open-end spinning machines. In the case of the machines which are available on the market, the slivers are withdrawn directly by the sliver feeding device of the individual spinning stations from the cans disposed in front of and partly below the spinning arrangement.
It is also known (German Patent Document DE-C 23 35 740), in the case of open-end spinning machines, to arrange the cans on a platform above the spinning machine and feed the slivers through guiding tubes to the spinning stations. These guiding tubes, which are provided with baffles, are to serve as an intermediate storage device which, on the basis of a special construction, is fed by a continuously running feeding device nevertheless intermittently. Then the sliver is to be guided through the respective guiding tube essentially without tensile stress.
The feeding of the fiber material in the form of slivers made available in cans is also known in the case of other fast-running spinning machines, such as wind-around spinning machines or air spinning machines. As a rule, these are one-sided machines, in the case of which the slivers withdrawn from the cans deposited on the rear side of the spinning machine are fed to the spinning stations from above. In this case, guiding devices for the slivers are provided in the form of pulleys and guide rods.
It is also known (German Patent Document DE-PS 817 572) to feed slivers in cans in the case of ring spinning machines, in which case the cans are deposited on platforms or in a space above the spinning machine. In this case, relatively long travelling paths are obtained with one or several vertical runs which lead to the risk that the slivers may hang out; that is, are drafted uncontrollably as a result of their own weight. Such an arrangement is therefore possible only for slivers which have a relatively coarse size and thus a relatively high strength.
However, the spinning of slivers of coarse sizes is very difficult on ring spinning machines. Since the ring spinning machines have only a relatively low delivery speed at the outlet of the drafting units, the feeding rollers of the drafting units--while the required drafting is taken into account--must run very slowly; that is, at rotational speeds of one revolution per minute and less. It is technically extremely difficult to let long shafts such as for the feeding rollers of drafting units, run at such low rotational speeds with sufficient precision. There is the risk that these shafts will rotate only jerkily so that no controlled draft is obtained. The feeding of the fiber material to be spun in cans has therefore not been carried out successfully in practice in the case of ring spinning machines.
In an older German Patent Application (P 40 41 112.5, PA 1170, P 9342), corresponding to U.S. application Ser. No. 07/809,141, filed Dec. 18, 1991, now abandoned in favor of U.S. continuation-in-part application Ser. No. 07/948,638, filed Sep. 23, 1992, which is no prior publication, it is suggested to provide guiding devices which comprise a transport belt which is provided with a mounting of needles which project toward the outside. The needles, which are arranged at relatively large distances of, for example 10 cm, are sloped toward the rear against the moving direction. By means of these needles, which pierce the sliver, the sliver is supported in the vertical direction.
It is an object of the invention to develop a spinning machine of the initially mentioned type in such a manner that fine slivers may also be fed in cans without the risk of faulty drafts, particularly in vertical portions of the transport path.
This object is achieved according to preferred embodiments of the invention in that the guiding devices comprise one belt respectively which transports the pertaining sliver and is equipped with holding elements which hold the sliver on its surface.
In the case of certain preferred embodiments according to the invention, it is achieved that the slivers are supported and are nevertheless moved in the transport direction. As a result, it is possible to feed also relatively thin slivers in cans; that is, slivers of sizes of approximately Nm 0.4 to 0.8. In this case, these fine slivers may also be transported in the vertical direction along larger travel paths. It is therefore possible to carry out a can feeding also in the case of ring spinning machines because, on the basis of the slivers with the fine sizes, while taking into account the draft, the feeding roller pairs of the drafting units still run at a sufficiently high speed so that a uniform circumferential rotating speed is ensured. By means of this can feeding, it will then be possible in the case of ring spinning machines to do without a premounted machine, specifically the flyer. In the case of other spinning machines, which are equipped with drafting units into which the slivers travel, it is possible to feed finer slivers so that then the drafting units may be simplified. For example, in the case of machines of this type, there is the possibility to use the three-cylinder drafting units which are customary today in the case of ring spinning machines, instead of five-cylinder drafting units.
Also in the case of open-end machines, the feeding of finer slivers results in advantages because then the opening-up work for the separating of the fibers is reduced so that, during the opening-up, the fibers are processed more carefully. It is therefore possible to spin finer yarns with less damaged fibers so that the yarns have a higher quality.
In contrast to the suggestion of the older patent application mentioned above, the sliver is mainly only held on its surface, for example, by lateral surfaces by means of a frictional engagement or on its supporting surface by means of adhesion to the belt. As a result, a damaging of the sliver is avoided.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.